Regulating means for gas-separating apparatus



E. A. BARBET. REGULATING MEANS FOR GAS SEPARATING APPARATUS.

APPLICATION FILED JUNE 25, 19]) Patented Nov. 1, 1921.

2 SHEETS- SHEET 1- E. A. BARBET. REGULATING MEANS FOR GAS SEPARATINGAPPARATUS.

1,395,466. APPLICATION FILED JUNE 25, I919. 1,

2 SHEETS-SHEET 2.

EMILE AUGUSTIN BARIBET, OF PARIS, FRANCE,

REGITLATING MEANS FOR GAS-SEPARATING APPARATUS.

To all whom it may concern:

Be it known that I, EMILE AUoUs'rIN BARBET, a citizen of the FrenchRepublic, residing at No. Rue de lEchelle, Paris, France, have inventedcertain new and use ful Improvements in Regulating Means forGas-Separating Apparatus, of which the following is a specification.

This invention relates to the application of apparatus and means ofregulat ng the speed of working to all apparatus for rectifying liquidair or liquefied gases of any kind, more particularly 'to the type ofrectifier forming the subject matter of my earlier application forLetters Patent Serial No. 215,679 of 6 February, A. D. 1918, saidrectifier being a continuous rectifier for liquid air and allowing ofseparating the whole of the oxygen and nitrogen in a state of urity inone distilling operation.

he improvements of the present invention are designed to assure aperfect regularity in the working of the rectifying a paratus. Theseimprovements allow of. 0 taining nitrogen and oxygen in a state ofabsolute purity, and of assuring a great con stancy of chemicalcomposition of the various extractions of rare gases which can beeffected by the invention, either when used simply for producing oxygenand nitrogen in a very pure state or for facilitating the subsequentrectification of the rare gases.

In the absence of a sufiicient regularity, disturbances may occur in theworking of the apparatus. As a matter of fact if during a certain periodof time there is allowed to issue from the bottom of the rectifier avolume of oxygen which is either insufficient or on the contrary isexcessive relatively to the quantity of oxygen entering the middle ofthe column in the form of air, the chemical composition of the liquidsof the plates is inevitably varied to a considerable degree.Particularly the zone of maximum concentration of the argon changes itsplace and it is no lon er possible to effect the extraction of thisimpurity at the appropriate stage, so that the nitrogen and the oxygenwill not remain pure. I

In other words, in order to produce nitrogen and oxygen in theperfection of purity, it is necessary to assure to the apparatus a fixedprocedure in working and it isthe object of this invention to apply acombina- Speciflcation of Letters Patent.

Application filed June 25,

Patented Nov. 1, 1921. 1919. Serial No. 308,621.

tion of regulating means such that the regularity of functioning of theprocess is automatically efi'ected.

The invention is illustrated in the accompanying drawings, in which--Figure 1 is a diagrammatic View of the improved apparatus.

Fig. 2 is a similar view of a modified form p f alportion 'of theapparatus shown in .1 11 order to avoid complicating the drawings aportion of the accessory devices of the rectifying column proper havebeen omitted.

The regulation is based on the adjustment of the exits of pure gaseswhich is effected once forall by hand, being based on the readings orindications of meters inserted in the pipes leading to the respectivegas-holders.

In the drawings only the two main exits are shown, namely N for thenitrogen and O for the oxygen, from the rectifier AA If the apparatus isconstructed to rectify 1000 cubic meters of air per hour, the sensitivecock 1 is so adjusted that the meter on the nitrogen exit will indicateexactly 790 cubic meters per hour, while the cock 2 must be so adjustedas to allow simultaneously only 210 cubic meters of oxygen to passthrough.

When this has been done it is merely necessaryto regulate the entry ofair into the apparatus in such a manner that the latter shall remainregularly at the desired rate of working.

For this purpose the special thermometer t for these low temperaturesmust be kept under observation to enable the temperature of ebullitionof each plate to be maintained at the requisite value. If the absolutetemperature is seen to drop from 1 to 2, this Will mean that there is arisk of having a small quantity'of nitrogenremaining in the oxygen inthe bottom. Vice versa, if the temperature rises from 1 to 2, there is'arisk of carrying a little oxygen over into the nitrogen.

The deliveries of the meters can only bemaintained if the pressure inthe gas-holders and the pressure inside the rectifier are constant.Therefore the first regulation to be made is that of the pressure of thegases in the rectifier, and in a of the apparatus.

For thi purpose a first regulator V W particular in the base of a knowntype is employed, but in which instead of 'water there is placed oilthoron hly freed from moisture which is not lia le to solidify in greatcold. I

The lower vessel is maintained through the pipe 20 at the pressure ofthe lower part a of the rectifier and the float '0 of V acts upon athrottle 3 provided 1n the air mlet pipe 31. When the pressure drops,the throttle will open a little more, and vice versa.

The air is shared between the nitrogen recuperators R and R through thepipe 32, and the oxygen recuperators B through the pipe33. Since'theloss of head due to the passage through the oxygen recuperators is lessthan in the nltrogen recuperators, there will be a tendency for greateramount of passage through the oxygen recuperators and then this airWlll. not be sufficiently cooled. This is obv1ated by inter osing avalve-cock 4 1n the p1pe 33. WlllCh is regulated accordingtothe'respective indications of the thermometers T and T placed on thepipes 34 and 35'with supply air to the column A A It is howevernecessary that the operator should be able to adjust the speed ofworking of the apparatus at will. For this purpose the bottom of thereservolr V 1s rovided with a cock y and connected by a ex! ble pipe 7to a reservoir Y capable of ascending and descending. This reservoir Yis suspended from a ulley W with a counterweight Z. a

Assuming that the apparatus is working, and the level in the lowervessel V is at 1 and that the operator wishes to diminish the admissionof'air. For this purpose he causes the level in the lower reservoir V torise from 1' to 2. If the movable reservoir is raised into its uppermostposition Y, and

' the cock y be opened gently, the liquid will pass from Y graduallyinto V, and the working pressure will be diminished by the vertical headcomprised between land 2'.

Assuming now that it i desired to accelerate the working and to lowerthe level of the incongealable liquid to 3'. :Y must be lowered intoa'position below V and y is opened gently. This time the liquid from Vwill rise inY. y must be closed as soon as the gage 21 is indicating thedesired level, and the working pressure will be increased by thedifierence in heat between 1 and 2'.

Regulation of the heating supplied by the compressed m'trogen.

The pressure existing in thelower part of the rectifier is the result ofseveral causes tor-pressure will be constant.

2. A loss of head due to the passage throu h the recu erators. This lossof head shoul likewise e assumedto be approximatel constant, because thedischarge of the nltrogen and the discharge of the ox 1glen are adjustedto a practically invariab e ourly rate.

3. A loss of head due to the bubbling of the air to be rectified. Thisair passes only over the upper plates. The regulator must maintain thevolume of this air constant, and therefore there is a loss of head whichwill be constant.

4. The heating produced in the lower part by the condensation of thenitrogen under pressure generates a certain hourly volume of oxygenwhich bubbles u in all the plates of the apparatus, those at t e bottomas well as those at the top.

It is this last bubbling up which must be regulated and renderedconstant because without this, if the heating temperature were to drop,the loss of head of the column would diminish, and the large regulator VV would deliver into the column an excess of air which would disturb theestablished rate of working. In other words the lar e regulator V Vworks well only if there is no fear of disturbance due to variation ofthe heating of the column.

- It is therefore very important to regulate this heating.

The gases which the worm E evolves by its action are alone to be causedto bubble in the bottom plates, that is to say, in the distilling plates(A They are therefore alone the cause of the difference of pressure tobe found between the lower part a and the level of the air inlet a. Eachtime the intensity of ebullition varies, the difierence of pressure willalso vary.

These variations will be obviated by. means of the second smallregulator V V the lower vessel of which is maintained at the pressureofthebase of the'column by the pipe 22, and the upper vessel of which iskept at the pressure of the air feed plate by. the pipe ,5. The same oilreservoir Y with which V is in communication through 1 with the bottomof 0 will allow the operator to vary the setting of this regulator atwill, but once he. has regulated the variation of the level of theliquid in the two vessels,

the regulator will maintain a corresponding and constant loss of head inthe apparatus. This regulatorV V controls the throttle 7 for theadmission of the nitrogen vapor through the pipe 26 and regulates itsadmission to the worm E. A At the exit of the worm there is situated aseparator E which allows only liquefied nitrogen to pass. It isadvisable to provide a liquid meter E behind this separator in order toascertain the degree of the heating efiected. v

5. There is another precaution to be taken.

' The nitrogen compressor J is liable to go the power.

wrong, to work too fast or too slowly.

The path of the nitrogen passing through the compressor J is as ollows:the gaseous nitrogen at the top of the column asses through the pipe 23,the recuperator and the pipe 9 to the compressor J, whence it passesthrough the pipe 24, the cooler K and the pipe 25, into the tubes K, andthrough the pipe 26 into the cooler-worm E; thence it passes through thedischarge cock E and the meter E and rises in the liquid state throughthe pipe 27 to the top of the column.

If the compressor is working .too fast, it will supply a too greatweight of compressed nitrogen, and this nitrogen being prevented frompassin by the throttle 7, the pressure will rise. he consequence is aloss of mo- In order to avoid this, it is suflicient to provide on thedelivery conduit of the nitrogen, for instance at the point 8, a safetyvalve adjusted to the desired pressure; the escape of nitrogen throughthis valve will return into the suction pipe 9 of, the compressor.

If on the contrary the compressor is working too slowly, there is a riskof there being no ebullition whatever in the apparatus owing to theabsence of a sufficient pressure,

of the nitrogen. If in these conditions the air should continue to enterthe apparatus, the whole system of working will be quickly destroyed. Itis absolutely necessary to avoid this eventuality.

With this object the pressure of the nitro en acts through the pipe 28against the un erside of a piston working in the cylinder 10; thispiston being suitably loaded by a spring 11 which can be more or lessstressed.

The piston is surmounted by a rod acting upon the lever 13 operating thevalve 12 controlling the air only. As soon as the necessary pressurebegins to drop, the valve 12 restricts the admission of the air. If thepressure drops to a point such at which there will be no ebullition ofthe oxygen, the valve will close completely.

There is still a further precaution to be taken: it is possible as amatter of fact that the compressor designed to supply the rectifier withthe thousand cubic meters of air per hour, should slackcn, and no longersupply sufllcient air. It is necessary that the operator should knowthis immediately in order to reestablish the normal working.

When this insufficiency of air supply occurs, the pressure in theapparatus drops, and therefore the float o of the large regulator V Vwill descend. If this descent is considerable it is desirable thatwarning should be given. The actual float has the function of givingthis alarm.

16 is a whistle rovided on the air supply duct. This whistle is set inoperation when the counter-weighted lever 17 is lifted. So long as thefloat is situated at a normal level, the chain passing over the twogrooved ulleys 14 and 15 will be slack, and the whlstle Wlll not sound.

f however the float descends to a sufficlent distance, the chain willbecome taut and will finally raise the lever 17 and thus operate thealarm whistle.

Owing to the provision of all these alarms, safety valves and automaticregulating devices, there is no further risk of the operator being takenunawares by the bad operation of the compressors, and the apparatus willyvor: with an automatic and faultless reguam y.

If desired a special whistle may be provided intended to give warningwhen the 35 nitrogen compressor is no longer giving sufficient pressure,and the valve 12 is about to close. The lever 13 can be readily arrangedto operate a whistle 18 whose sound will differ in tone from that of thewhistle 16.

The absolute regularity of the working of the apparatus will be stillbetter attained if the air to be rectified is admitted exclusively' inthe liquefied form. Moreover, owing to this new feature in the working,the distilling plates will work to their fullest extent as a consequenceof the great renewal of the descending li uid.

My aforesaid patent app ication of 6 Feb- 100 ruary, 1918, Serial No.215,679, has already shown that it was easy "to liquefy 79/100 of theair by the exchange of cold units with the 79/100 of pasteurized liquidnitrogen issuing. at m.

As regards the 21/100 corresponding to the extraction of the oxygen(which takes place in the gaseous state), recourse is had to theartifice illustrated in Fig. 2.

In this figure in order to simplify the 110 drawing only the centralportion of the apparatus ,is shown; the left and right hand portions ofFig. 1 remain the same.

Behind the recuperator R there is another exchanger R in which by means115 of the cook 36 a desired quantity of liquefied nitrogen is passedwhich is extracted from E This nitrogen expands and therefore cools toabout 194 C. and becomes cold enough to liquefy the air 120 coming fromB through the pipe 37. The liquefied air issues through a dischargedevice, passes through a meter E and rises to the feeding plate. Asregards the nitrogen which is gasified by way of exchange, 125 it risesthrough the pipe 38, enters the top of the rectifier and returns to thecompressor. A small additional quantity of nitrogen thus requires to becompressed and cir-' culated by the compressor, but the expense 130 iscompensated by the more regular working of the apparatus and by theincrease 0 the plates A. in refining power. I

All the regulators and alarms hereinbefore are more particularlyrequired when it is desired to extract nitrogen and oxygen in a state ofpurity and to obtain the argoniin a high degree of concentration.

What I claim is w 1. In rectifying apparatus for treating mixedliquefied gases, regulatin devices automatically operatedbythevariations of pressure in the various parts of the apparatus tomaintain regular working of said apparatus, said regulating devicescomprising in combination a regulator operated by the rise or fall ofpressure at the base of the rectification column and controlling thesupply of the liquid gas to be rectified, a second in pressure betweenthe feed chamber. and the base of the rectification column andcontrolling the supply of heating medium to the rectification column, avalve which causes any excess of heating medium to be returned to thepump supplying said heating medium and a valve which reduces the amountof liquid fed to the rectification column should the pump supplying theheating medium deliver less than-the requisite amount of said medium.

2. In rectifying apparatus for treating mixed liquefied gases,regulating devices automatically operated by the variations of pressurein the various partsof the apparatus tomaintain regular working of saidapparatus, said regulating devices compris ing a regulator provided witha vessel containing a fluid maintained under the same pressure as thebase of the. rectification column and a float adapted. to rise and fallaccording to the variations of pressure at the base of said column andin so doing to operate a valve controlling the inlet for the fluid to berectified, the level of the fluid in said controlling device beingadapted to be set to a'desired level by adjustment of the height of anadjustable reservoir containing regulator operated by the difference.

fluid in communication with the fluid contained in the said vessel ofthe regulator.

3. In rectifying apparatus for treating mixed liquid gases, regulatingdevices automatically operated by the variations of pressure inthevarious parts of the apparatus to maintain regular working of saidapparatus, said regulating devices comprising a re ulator provided witha vessel containing a iquid under a pressure which is that due to thedifference of pressure existing between the feed chamber and the base ofthe rectification column, and a float adapted to rise and fall accordingto the variations of the difference of said pressures and in so i doingto operate a valve controlling the inlet for the heating medium suppliedto the rectification column the level of the fluid in said controllingdevice being adapted to be set to a desired level by adjustment of theheight of an adjustable reservoir containing fluid r in communicationwith the fluid contained in the said vessel of the regulator.

4. In rectifying apparatus for treating mixed liquefied gases,regulating devices automatically operated by variations of pressure inthe various parts of the apparatus said regulating devices comprising incombination a regulator operated by the rise or fall of pressure at thebase of the rectification column and controlling the supply of theliquid gas to be rectified, a second regulator operated by thedifference in pressure between the feed chamber and the base of therectification column, said devices comprising vessels containing fluidthe level of which for both regulators is adapted to be set to a desiredlevel by the adjustment of one adjustable reservoir containing fluid incommunication with the fluid contained in the fluid containing vessel ofthe regulators. 1 5. In rectifying apparatus for treating mixed liquidgases, regulating devices automatically operated by the variations ofpressure in the various parts of the-apparatus to maintain regularworking of said apparatus, said regulating devices comprising anadjustably loaded valve placed. in the circuit of-the compressorsupplying heating medium to the rectification column, said valveoperating to return any excess of heat AUGUSTIN BARBET.

